1. Field of the Invention
The present invention relates to an electrical connector assembly, and more particularly to an electrical connector assembly with a heat dissipating device to efficiently dissipating heat generated from a CPU (Central Process Unit) mounted within the socket assembly.
2. Description of the Prior Art
U.S. Pat. No. 5,722,848 issued to Lai on Mar. 3, 1998 discloses a typical connector socket, and which is generally referred to as a ZIF (Zero Insertion Force) socket. In general, the socket includes a base with a plurality of contacts assembled therein, and a cover moveably attached to the base. A lever with a cam mechanism is arranged between the base and cover to drive the cover from a first position to a second position. When the lever is located in a vertical position, the cover is located at the first position, in which a hole in the cover is completely in aligned with a corresponding passageway in the base. In this position, pins of the CPU can be inserted from the cover into the passageway without any engagement with the contact. When the CPU is properly seated on the cover, then the lever is moved from the vertical position to a horizontal position, and simultaneously driving the cover from the first position to the second position. During this process, the pins of the CPU are then in contact with the contact within the base. The Lai '848 is specially directed to a desk-top computer.
CPU socket used on notebook is substantially similar to what is used on the desktop computer, and the only difference is on the lever used on '848 patent was replaced by a screw with a cam mechanism. When the screw is driven or rotated, the cover is driven to move along the base, therefore the pins of the CPU are then in contact with the contact within the base, and no detailed description is given here.
U.S. Pat. No. 7,001,197 issued to Shirai on Feb. 21, 2006 discloses another type of socket, and which can be generally called LGA (Land Grid Array) socket. The original pins type of chip occupies more space on the bottom surface of the CPU. In order to increase input/output speed, conductive pads are introduced to replace the pins so as to directly and electrically contact with contact terminals within the socket. No doubt, the speed is increased.
As clearly shown in Figures of Shirai '197, it is different configuration from to what Lai '848 discloses. The socket generally includes a metal stiffener with a housing securely supported therein. Then a metal clip is pivotally assembled to the stiffener. On the other hand, the clip is pivotally assembled to one side of the stiffener and when the clip is closed to the stiffener, the lever has a cam which can lock the clip to a closed position. By this arrangement, the CPU is seated on the housing before the clip is closed, and then the clip will tightly press the CPU toward the housing for ensuring proper electrical connection therebetween.
Shirai '197 can be applied to the desktop computer for which has more room for the operation of the lever, while it is almost impossible to apply Shirai '197 directly to the notebook in view of its compact, and thin space.
Another factor to be considered is the configuration of the CPU. The CPU generally includes a substrate and a die mounted upon the substrate. Even the CPU is rigid, it is still vulnerable to deform or warp for downward force applied thereon is not evenly distributed. In Shirai '197 patent, the die is not pressed by the clip which has a window for it. The die is in direct contact with a heat sink. As a result, when applying the so-called LGA socket to notebook, how to provide a mechanism functionally similar to Shirai '197, while keep downward force evenly distributes to both die and substrate, is a motive for the present invention.
The configuration of heat sink is another factor to be considered. Typically, the heat sink device includes a bottom plate and a plurality of parallel heat sink clip disposed on the bottom plate. As the heat sink device generally has a big volume, it applied to the desktop computer is ok, while it is almost impossible to apply to the notebook in view of its compact and thin space.
Therefore, there is need to supply an improved electrical connector assembly with a heat dissipating device.